Signaling system.



J. S. GARVIN.

SIGNALING SYSTEM.

APPLICATION FILED MAR. 18. 19:8.

Patented Dec. 31, 1918.

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b Ar/k UNITED sra'rns PATENT orFioE.

JOHN S. GARVIN, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY,

TNCORPORATED, OF NEW YORK, N.

Y., A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

To all whom it may concern:

Be it known that'I, JOHN S. GARVIN, a citizen of the United States, residing at New York, in the county of Bronx, State of New York, have invented certain new and useful Improvements in Signaling Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to signaling systems,

and more specifically to signaling systems which are particularly applicable to signaling on composite telegraph and telephone circuits.

In certain telephone systems, particularly those in which both telegraph and telephone circuits are combined, it is desirable to use for signaling purposes currents of different frequencies.

In composite tele aph and telephone systems it is particular y desirable to use higher frequency currents of approximatel 133 cycles per second for operating a si' a associated with the telephone service without interfering with the operation of the telegraph v quency signaling current usually employed in connectlon with the telephone service into the higher frequency current suitable for transmlssion over the composited line with out impairing the telegraphic service.

Systems of this'general character have been heretofore proposed and the present invention is an improvement in such systems having for its object the increasing of the ringing range or length of line over which signaling may be easily accomplished and the provision of an arrangement in which the apparatus may be easily maintained without the necessity of frequent adjustments.

To attain this object, in accordance with one feature of this invention, a high impedance polarized relay with a vibratory armature is bridged across the conductors of a composited telephone line at a point intermediate the ends of the line. This relay is responsive to a signaling current of any frequency which may ordinarily be applied at either end of the line and selectively controls two local circuits containing two relays, one of which is exclusively responsive to one of two definite frequencies, while the other is responsive to either of the two definite frequencies. Either of the relays controls means for connecting to one end of the line a source of signaling current separate from (that which is impressed on the other end of the line and the first mentioned relay con- 1trols the circuit of the second mentioned re- These and other features not specifically mentioned above will more clearly appear from the following specification and the annexed drawing in which the figure shows diagrammatically a sufficient portion of one end of a composited telephone line to illustrate the invention.

In the accompanying drawing, the jack 1 and the drop 2 represent the terminus of a telephone line which is composited. Although not shown in the drawing, since it is unessential to the proper understanding of \the invention, it is understood that the usual telephone operators cord circuit equipped with the ordinary ringing device is available for connection with jack 1. The line conductors 19 and 20- may be assumed as being connected with the line side of a regular composite circuit (not shown) which is associated with the telephone line under consideration, and at the distant end of the telephone (also not shown) there may be an arrangement similar to that shown in the drawing.

It is thought that'the invention may be more clearly understood from the following description of the operation of thesignaling system. y 1

Assume that the operator at'the station at at which the jack and drop are located de- Speciflcation of Letters Patent. Patented Dec, 31 1918, Application filed March 18, 1918. Serial No. 223,185. I

sires to operate the telephone-signal at the other end of the composited line. The operator inserts the plug of the usual cord circuit into the jack 1 and operates the ordinary ringing key provided in such cord circuit to impress upon the line a signaling current of the usual frequency of 16%,cycles per second. This current will flow through condenser 3 and the winding of relay 4. Since relay 4 is so designed that it will respond to a current of any frequency, the armature thereof will vibrato in synchronism with the alternations of the signalin current being impressed upon the line, which in this case rela 6, to the lower terminal of resistance 7, w ere it joins the first circuit. When the armature is in this position it will be assumed that the direction of flow of current is from batteries 5 and 9, throu h the windings of relays 6 and 10 and the resistance 7. Correspondingly, when the armature of relay 4. closes its right-hand contact, two other circuits are completed, the first of which may be traced from ground through battery 9,-

winding of relay 10, right-hand contact of .relay 6, resistance 7', right-hand contact of relay 4, resistance 11, and battery 12. The second circuit may be traced from ground, through battery 5, winding of relay 6, to the lower terminal of resistance 7, where it joins the first traced circuit. Inasmuch as the bat- '-tery 12 is one havin approximately twice the volta e of either attery 5 or 9, and due to the di erential series relation existing between batter 12 and each of batteries 5 and 9, the direction of current flow through the relays 6 and 10 and the resistance 7 will be opposite to that of the current flow through such relays when the left-hand contact of relay 4 is closed.

These continuous reversals of the direction offiow of the current through the resistance 7 and the relays 6 and 16, produce alternating current effects which are in synchronism with the current operating relay 4, which in this case has been assumed asbein 16% cycles per second.

A ternating current relay 6, which is responsive to currents having such a frequency, will therefore be immediately operated, opening the circuit of relay 10 and preventm the operation of the latter relay, which will not respond readily to a current of such frequency, since it is designed to respond primarily to a current having a he queue of approximately 133 cycles per secon i The opening of the left-hand contact of relay 6 interrupts the normal circuit existing from battery 13, through winding of relay 14: and the left-hand contact of relay 6 to ground. Relay 14 is thereby released, com leting a circuit from battery, through win ing of relay 16 to ground. hereupon relay 16 operates, connecting the source of signaling current 17 to the line conductors secon remainder of the apparatus at the calling station. Since the source of signaling current 17 is adapted to furnish current having a fre uency of approximately 133 cycles per a current of such frequencyis 1mpressed cuit to the distant station, which portions of the completed connection have been omitted from the draw ng for the sake of clearness.

When the operator ceases the application of the signaling current, all of the apparatus returns to. theficonditions shown on the drawing.

ate relay 4 in the same manner as before except that the armature thereof will vibrate 1n synchronism with the alternations of the higher frequency current. The closing of the contacts of relay 4' willcomplete circuits through relays 6 and 10 which-are similar to those previouslydescribedbut the alter;

nating current effects produced therein will agree with the higherzfrequency Relay 10 being primarily responsive to .currents of-a frequency of 133 cycles per second will therefore immediately operate, while relay 6, being unresponsive to currents of such frequency, will remain inert. In operating, relay 10 interrupts the 110911181 circuit from battery 13 through winding of relay 15 and contact of relay 10 to ground. Relay 15 is therefore released, closing a circuit from battery 13 through contact of relay 15 and winding of'relay 21 to ground.

.Relay 21 operates, disconnectin .from the line the conductors leading to t e 'tip and ring contacts of the jack 1 and connecting to such conductors a source of signaling cursEsT AVAILABLE cor- -19 and20 and disconnecting therefrom the upon the line conductors 19 and 20 and is transmitted over-the composited circurrent. 1

rent 18, thereby providing a current having a frequency of 16% cycles per second for op-'" eratingthe dro 2. When the application of the higher requency current 1s discontinued at the distant station, all apparatus returns to the conditions shown as in the previous case. 1

If desired, battery 12 may be omitted and resistance 11 may be connected directly to ground. With such an arrangement the op eration of the system. will be identical witl.

that described, except that pulsating in:

stead of alternating current effects w1ll in present in the circuits, including the wind in of relays 6 and 10.

twill thus be evident that it is ossibl with the present invention, to emp oy on relay which does not-require the refinemen of adjustment necessary to absolutely limi its operation to a single frequency instead 0 using relays exclusively responsive to each ,meansconnected to intermediate point thereof responsive to a frequency desired to be translated.

What is claimed is:

1. In a signaling system, a line circuit, the line circuit at an signaling current of any frequency impressed upon either end of the line, a first switching means selectively controlled by said means and responsive to currents of different frequencies, a second switching means selectively controlled by the first mentioned means and responsive to one of such currents to render the first switching means inoperative, and means controlled by the second switching means to connect a separate source of signaling current to the other end of the line and to prevent the transmission thereto of the signaling current op- .erating the second switching means.

2. In a signaling system, a line circuit, a pair of local circuits, means responsive to a periodically varying current of any fre quency impressed on either end of, the line for producing a current in each local circuit in synchronism with the impressed current, means in one of the local circuits responsive to a single-frequency to interruptthe other local circuit, and means controlled by the last mentioned means to connect to the line a signaling current having a predetermined frequency differing from that of the impressed current.

3. In a signaling system, a line circuit, a pair of local circuits, nected .to the line at responsive to a an intermediate point periodically varying current of any frequency impressed upon either end of the line for producing in the local circuits a current in synchronism with the impressed current, a relay in one local circuit respons1ve to a current of a partlcular frequency 'local circuit to connect a a polarized relay con-' to interrupt the other circuit and a plurality of relays controlled by the last mentioned relay to interrupt the line circuit and to connect to one portion thereof a signaling current having a predetermined frequency differing from that of the impressed current.

4. In a signaling system, a line circuit, a pair of local circuits, a polarized relay bridged across the line at an intermediate point thereof and having an armature adapted to vibrate in synchronism with the alternations of any signaling current impressed one either end of the line for producing'in the local circuits a current in synchronism with the impressed current, a relay in one local circuit responsive to either of two predetermined frequencies, a relay in the other local circuit responsive to .one of the two predetermined frequencies and adapted to render the first mentioned local circuit ineffective, and means operative upon the operation of the relay in the second mentioned periodically varymg current to the line for transmission thereover and to disconnect therefrom the impressed current.

5; In a signaling system, a line circuit, means responsive to alternations of any frequency impressed on the line for generating alternations in synchronism therewith in a local circuit, switching means included in the local circuit responsive to alternations of a plurality of frequencies, switching means also included in the local circuit responsive to one of said frequencies, and

JOHN S. GARVIN. 

